Incandescent structure suitable for lighting.



Ilnrrnn STATES PATENT OFFICE.

JOHN HENRY HILL DUNCAN AND HARRY THEODORE BARNETT, OF

. LONDON, ENGLAND.

INCANDESCENT STRUCTURE SUITABLE FOR LIGHTING.

SPECIFICATION formingpart of Letters Patent No. 659,515, dated October 9, 1900.

Application filed October 26, 1899.

To all whmn it nuty concern.-

Be it known that we, JOHN HENRY HILL DUNCAN, residing in the city of London, and HARRY THEODORE BARNETT, residing in Teddington, London, county of Surrey, England, subjects of the Queen of Great Britain and Ireland, have invent-ed Improvements in Incandescent Structures Suitable for Lighting, of which the following isa specification.

This invention has reference to incandescent structures suitable for use as light-giving media when subjected to the action of heat-as, for example, when subjected to the action of non-luminous flames; and it has for its objects, inter alia, to improve the color of the light furnished by such structures, to increase the strength ,of the structures, and to facilitate their manufacture, so that without departing from the more satisfactory proportionate combinations of refractory substances incandescent structures can be produced Whose color or tint of light and strength can be varied Within reasonable limits.

Most incandescent structures of high efficiency as now prepared emit light other than white -2'. e., a light possessing a preponderance of some one or more of the primary colorsas,for instance, the green-tinted-lightemitting IVelsbach mantles and the orangetinted-light-emitting mantles of the chrome class. According to this invention such variously-tinted-light-emitting bodies are united or combined mechanically in one composite structure in'such a manner that the selectively-emitted varying colors or tints of light combine to produce an effect more pleasing to the eye or better suited to the purpose in view than heretofore. To this end we spin, double, knit, cable, interweave, overweave, or otherwise mechanically connect or associate separate filaments, threads, cords, rods, fabrics, or other shaped bodies, hereinafter referred to as filaments or threads, containing or consisting of different proportionate combinations of incandescent oxids which yield lights of different color or tint into one composite structure. By varying the number or size of the filaments containing each of the said oxids or combinations of oxids used to form one thread or the number of threads of each employed to construct one composite Serial No. 734,878. (N0 model.)

structure-it may be a mantleor the positions of such differently-constituted members of such a thread, respectively, in relation to the position most favorable for radiating light or for becoming heated to a maximum temperature we are enabled to produce incan-' descent bodies whose color or tint of light can duce an illumination of more pleasant color than would be obtainable from either one of them alone.

The filaments or threads of refractory-oxidbearing material or of refractory oXid which are to be united according to this invention may be formed by the Welsbach or Knofler processes or otherwise.

One or other of the kinds of filaments or threads constituting a composite incandescent structure according to this invention may be stronger than the remainder and so render the whole mantle more durable or by reason of the said strength may allow a weaker substance-perhaps of higher light emissivity or possessing some other advantageto be used in connection with it. In some cases we adopt this compound construction of an incandescent structure, whereby it contains portions of differing constitution without particular reference to the color of light emitted for the reasons last above stated.

Incandescent mantles for use with gasflames can be made according to this invention in various ways.

The following are examples of mantles giving a golden-white light.

First. Two lengths of cotton thread are soaked each in dilferent solutions, one solution being such as to yield an incandescent body giving alight of greenish tintfor example, the Well-known mixture or compound of about ninety-nine per cent. thoria and one per cent. ceria-and the other solution being too such as yields an incandescentbody contain-' ing fifty per cent. thoria, forty per cent. alumina, and ten per cent. chromic oxid, soaked threads are dried and knitted, woven, plaited, or otherwise intertwisted to form a mantle. The two threads may he knitted in such a manner that the mantle is composed of alternate rows of thoria-ceria and thoriaalumina chrome threads, or two or more rows of either kind of thread may be used to one of the Other. Another mode of making such mantles is to knit the fabric into a continuone length composed of alternately-arranged short sections of the diiferent kinds of thread, so that mantle lengths may be cut therefrom whose upper and lower port-ions are of different constitution. Mantles made by a weaving process may have the different kinds of threads equally distributed in the fabric, or one kind of thread may be chiefly at the inner surface of the mantle, while the other kind is on the exterior surface of the mantle.

Second. Filaments containing two dilferent mixtures of incandescent oxids are separately produced by the well-known Knofler or some similar process and the two kinds of filaments being doubled- 6. e., twisted together to form a composite thread which is made into mantles in the usual Way. One kind of filament may contain thoria and coria in or about the usual proportions and the other kind alumina chromic oxid and zirconia or thoria, a satisfactory prescription for the latter being thoria thirty-five per cent, chromic oxid five per cent., and alumina sixty per cent, the alumina and thoria being conveniently added to the Knofier collodion in the form of nitrates of aluminium and thorium and the chromic oxid as chromic acid, and the two kinds of filaments being used in the proportion of twelve thoria-ceria filaments to three of the other kind.

Incandescent mantles made according to theforegoing examples give a light of goldenwhite color which does not become green in tint even when the mantles are well worn.

It will be obvious that more than two kinds of threads or filaments may be used and that ditferent kinds of impregnated threads might be doubled together to form one larger thread from which mantles can be made in the same way. as from the composite Knofler thread and also that Knofler filaments of differing kind or composition need not necessarily be united into one thread, but might be made secure this strengthening effect without appreciably modifying the color of the light furnished by the thoriaceria threads or filaments, the chromic oxid may be omitted from the, prescription. If desired, some other strengthening osid or oxids, such zirconia or silica, maybe used in place of the alumina.

As hereinbefore stated, it is sometimes advantageous to cablet'. e., to twist an external covering over a coretwo or more kinds of filaments or threads together to constitute one larger thread, and in this case one kind of thread or filament may constitute the core, while another kind constitutes the lapping or covering. When the core of thecabled thread is of material which contracts more than the lapping or covering, the effect is to bow or buckle the turns of lapping or covering material in such a manner that they are more readily permeated and heated by the flame in which the mantle is placed than would otherwise be the case. Sometimes the core may contain a larger proportion of some constitu out than it would beadvisable to employin threads or filaments which were to be Wholly exposed. A durable thread of this kind may have a core of thoria-ceria in which the ceria amounts to as much as or more than ten per cent-., by weight, of the thoria present and a lapping or covering in which the thoria contains little or no oeria.

It is to be understood that we are aware that it has heretofore been proposed to strengthen mantles by the addition to the mantle-body of supplementary threads or metallic wires applied to certain portions thereof; but such threads or wires are local only in action, and owing to the variable contraction that takes place between the mantlebodies and the supplementary threads or wires the latter tend to disintegrate the mantle-bodies rather than to strengthen them.

In incandescent bodies according to this invention the differently-constituted threads, filaments, or the like are united together in the process of manufacturing such bodies, as hereinbefore described, whereby a more equally-distributed strengthening efiect can be obtained without tending to disruption by reason of unequal contraction taking place between the diiferent kinds of threads, filaments, or the like constituting the incandescent body.

What we claim is- 1. An incandescent structure suitable for lighting, comprising filaments or threads of difierent refractory substances arranged in proximity to each other some of the filaments or threads being adapted to emit light of a different color to that emitted by the other filaments or threads substantially as described for the purpose specified. 2. An incandescent structure for lighting comprising mechanically-associated filaments or threads containing diflr'erent substances or compounds, some of the filaments or threads being adapted to emit light of a different color to that emitted by the other filaments or threads substantially as described for the purposes specified.

3. An incandescent structure comprising mechanically-associated filaments or threads containing differing substances or compounds,one or some of which is or are adapted to complement the color of the light emitted by one or some of the others.

4. An incandescent structure comprising mechanically-associated filaments or threads containing differing substances or coinpounds, one or' some of such filaments or threads being adapted to give alight of greenish tint and another or others a light of ruddy color.

5. An incandescent structure built up of interlaced filaments or threads one or some of which contain or containsa substance or compound adapted to complement the substance or compound contained in one or more of the other filaments or threads.

6. An incandescent structure built up of threads each of which consists of difitering' kinds of filaments adapted to complement each other as to the color of light emitted and 1 as to strength as set forth.

other substantially as herein described for the purposes set forth. v

Signed at 39 Coleman street, London, E. 0., England, this 18th day of October, 1899. JOHN HENRY HILL DUNCAN. HARRY THEODORE BARNETT. Witnesses:

O. H. WADMAN, H. E. SPINNEY. 

